Tools to precisely regulate gene expression in single cells or whole organisms are reported online this week in Nature Methods. The research could prove useful in the field of developmental biology where specific patterns of expression are central to many unanswered questions.
To understand the function of genes, it is advantageous to induce their expression in a live organism while controlling the spatial and temporal aspects of expression. With this in mind, Sidney Cambridge and colleagues modified a system known to work in cell culture so that it also worked within organisms.
The authors took small molecules known to activate genes adjacent to a particular promoter and inactivated these molecules by linking them to UV light-sensitive chemical compounds ― a process known as caging. Exposing cells containing caged molecules to innocuous levels of UV light removes the cage and allows activation of the gene regulated by the molecule-sensitive promoter. By precisely timing and localizing the activating light, the authors induced gene expression in single cells as well as whole organisms of mouse embryos and tadpoles.